CN104243121B - In a kind of Massive mimo systems based on cell sectoring pilot distribution method - Google Patents
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Abstract
In the invention discloses a kind of Massive mimo systems based on cell sectoring pilot distribution method, comprise the following steps：1) the base station end configuration M root antennas in Massive mimo systems are set, the cell of K UE and L circulating type is provided with Massive mimo systems simultaneously, and each user one antenna of correspondence, then each cell is divided into N number of sector, then the quantity of mutually orthogonal pilot tone is 3N/2, if each sector one user of correspondence；2) determine the distribution of pilot tone in each sector, complete the distribution of pilot tone.The present invention can effectively suppress pilot pollution, while more users can be serviced.
Description
Technical Field
The invention belongs to the field of wireless communication, relates to a pilot frequency distribution method, and particularly relates to a cell sectorization-based pilot frequency distribution method in a Massive MIMO system.
Background
In the Massive MIMO technology, spatial multiplexing and interference cancellation (increasing the power of a useful signal and thus increasing the signal-to-interference ratio to reduce the interference) are implemented by using a plurality of antennas at a base station, which has become one of the key technologies for improving the system. In a Massive MIMO system, users in the same cell need to transmit mutually orthogonal pilot sequences to achieve channel estimation. Unfortunately, when the coherence time is short or the number of users in a cell is large, there are not enough orthogonal pilots to allocate to the users. Therefore, there are users using the same pilot frequency in different cells, and these users interfere with each other during channel estimation, and this interference is called "pilot pollution".
At present, algorithms for suppressing pilot pollution in a Massive MIMO system are roughly classified into three types: the first type is based on the approximate orthogonality of channel vectors, and utilizes eigenvalue or singular value decomposition to blindly estimate channels, although pilot frequency overhead is saved, the algorithm is only suitable for slowly-varying channels and is limited by the problem of channel phase ambiguity; the second type is based on a cooperative base station, and utilizes second-order or high-order channel statistical information to distinguish interference users, although the algorithm can inhibit pilot frequency pollution, the algorithm needs to establish cooperation between base stations and obtain prior information of a channel; in a third type of uncooperative system, through the structural design of pilot frequency, different users are allocated with pilot frequency sequences on mutually non-overlapping time slots, and the algorithm saves the pilot frequency overhead and inhibits the pilot frequency pollution, but the number of users served in a cell is reduced.
In summary, it is necessary to design a non-base station cooperation scheme for Massive MIMO system, which can effectively solve the problem of pilot pollution suppression and serve more users.
Disclosure of Invention
The present invention is directed to overcome the above disadvantages in the prior art, and provides a cell sectorization-based pilot frequency allocation method in a Massive MIMO system, which can effectively suppress pilot frequency pollution and serve a large number of users.
In order to achieve the above object, the pilot frequency allocation method based on cell sectorization in the Massive MIMO system according to the present invention comprises the following steps:
1) setting a base station end in a Massive MIMO system to be configured with M antennas, simultaneously setting K UEs and L surrounding cells in the Massive MIMO system, wherein each user corresponds to one antenna, dividing each cell into N sectors, and sequentially numbering the sectors in each cell in an anticlockwise direction, wherein the position of a first sector in each cell is the same, the number of mutually orthogonal pilot frequencies is 3N/2, and each sector is set to correspond to one user;
2) obtaining a cell model according to a sector uniform division method, then dividing all sectors in the cell model into N/2 types of directions, wherein the ith type of direction is the direction from the ith sector to (N +2i)/2 sectors, wherein i is more than or equal to 1 and less than or equal to N/2, then averagely dividing the L surrounding cells into N coverage areas by taking each sector in a middle cell as a vertex, then the total number of the sectors in each coverage area is L, then dividing the sectors in the coverage areas according to the N/2 types of directions, then averagely dividing all pilots into N/2 pilot groups, then the number of the pilots in each pilot group is 3, then sequentially distributing the pilot groups to the various directions, then circularly distributing the pilots in the pilot groups to the sectors in the corresponding type of directions, and enabling each cell to have the pilot groups at the same time, and the pilot frequencies corresponding to the adjacent sectors are different;
meanwhile, the number of pilots in each coverage area is determined by the following method:
for each coverage area, N pilot frequencies are randomly taken out from 3N/2 mutually orthogonal pilot frequencies and are arranged in 2(L-1)/3 sectors in the coverage area, wherein the probability of arranging the pilot frequencies in each sector in the coverage area is 2(L-1)/3N after the arrangement is finished, then the rest N/2 pilot frequencies are distributed to the rest (L-1)/3 sectors, and the pilot frequency distribution based on cell sectorization in a Massive MIMO system is finished.
N is 2, 4, 6 or 12.
L is 19, the pilot setting power is 13db, and the transmitting power of the base station end is 20 db.
The radius of each cell is 600m, and in the process of signal transmission, the coherent time comprises two time slots, and each time slot is 0.5 ms.
Each cell is equally divided into N sectors according to the smart antenna technique.
The invention has the following beneficial effects:
in the pilot frequency distribution process, each sector is averagely divided into N coverage areas by taking each sector in a middle cell as a vertex, then the sectors in the coverage areas are divided into a plurality of rows, all the pilot frequencies are averagely divided into N/2 pilot frequency groups, then the distribution is carried out, each cell simultaneously has each pilot frequency group, the pilot frequencies corresponding to the adjacent sectors in the same row are different, in addition, for the problem of the number of the pilot frequencies in each coverage area, N pilot frequencies are randomly taken out from 3N/2 mutually orthogonal pilot frequencies and are arranged in 2(L-1)/3 sectors in the coverage area, then the rest N/2 pilot frequencies are distributed into the rest (L-1)/3 sectors, thereby completing the distribution of the pilot frequencies, after the pilot frequency distribution method of the invention is applied, the problem of pilot frequency pollution can be effectively solved, and the number of users of service is increased.
Drawings
FIG. 1 is a model of a Massive MIMO system according to the present invention;
FIG. 2 is a scheme for allocating pilots in the present invention;
FIG. 3 is a diagram of a conventional time-shifted pilot structure;
FIG. 4 is a diagram of a time-shifted pilot structure according to the present invention;
FIG. 5 is a graph of cell capacity as a function of antenna number after application of the present invention to six sectors;
FIG. 6 is a graph of cell capacity with the number of antennas for different sector division configurations according to the present invention;
fig. 7 is a graph of cell capacity as a function of pilot transmit power in the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
referring to fig. 1, the pilot allocation method based on cell sectorization in the Massive MIMO system according to the present invention includes the following steps:
1) the scenario of the Massive MIMO system is set as follows: base station terminalConfiguring M antennas, arranging K UEs and L surrounding cells in the system, wherein each user corresponds to one antenna, users in the L cell firstly transmit tau × 1 dimensional signals psi to respective base stationslk(K is 1, …, K), after estimating the channel of each user, the base station uses M × K dimension precoding matrix akAnd transmitting the data to K users after precoding. When the channel coefficient between the mth antenna of the jth base station and the kth user of the ith cell is represented as gjlmkThen the signal received by the jth base station can be expressed as
Wherein,hjlmkβ is the small scale fading coefficient between the mth antenna of the jth base station and the kth user of the ith celljlkIs a large scale fading coefficient, Ψ, between the jth base station and the kth user of the ith celll＝[Ψl1Ψl2…ΨlK]T，prIndicating the pilot transmission power, W, of the userjExpressing the additive white Gaussian noise of the jth base station end, obedienceDistributing, and then numbering the sectors in each cell in sequence in the anticlockwise direction, wherein the position of the first sector in each cell is the same, the number of the mutually orthogonal pilot frequencies is 3N/2, and each sector is set to correspond to one user;
2) obtaining a cell model according to a sector uniform division method, then dividing all sectors in the cell model into N/2 types of directions, wherein the ith type of direction is the direction from the ith sector to (N +2i)/2 sectors, wherein i is not more than N/2, then averagely dividing the L surrounding cells into N covering areas by taking each sector in a middle cell as a vertex, then the total number of the sectors in each covering area is L, then dividing the sectors in the covering area according to the N/2 types of directions, then averagely dividing all pilot frequencies into N/2 pilot frequency groups, then the pilot frequency in each pilot frequency group is 3, then sequentially distributing the pilot frequency groups to the various directions, then circularly distributing the pilot frequencies in the pilot frequency groups to the sectors in the corresponding type of directions, and enabling each cell to have the pilot frequency groups at the same time, and the pilot frequencies corresponding to the adjacent sectors are different;
for example: referring to fig. 2, if the number of cells is 19, and the cell is uniformly divided into six sectors by using the smart antenna technology, the number of mutually orthogonal pilots is 9, and the 9 mutually orthogonal pilots are respectively denoted by a, B, C, D, E, F, G, H, and J, and each coverage area is composed of 3 coverage areas in the column direction: sector 2 and sector 5 of each cell are covered in direction 1(Dir 1); sector 3 and sector 5 of each cell are covered in direction 2(Dir 2); sector 1 and sector 4 of each cell are covered in direction 3(Dir 3). Allocating the 9 sets of orthogonal pilot groups in step (1) to users in the 3 directions: pilot frequency groups A, B and C are distributed to users on Dir 1; pilot frequency groups D, E and F are distributed to users on Dir 2; pilot groups G, H, J are allocated to users on Dir 3.
The 3 pilot groups in each sub-direction are cyclically allocated to the sector users in the direction, so as to eliminate the interference among the users multiplexing the same pilot. For example, Dir 1 consists of 5 sub-directions, and in each sub-direction on Dir 1, the orthogonal pilot group number assigned to the sector user is a-B-C-a-B-C, and the top sector in each sub-direction is defined as the starting sector. In each direction, different orthogonal pilot frequency groups are distributed to the initial sectors in different sub-directions to ensure the minimum inter-sector interference between adjacent sub-directions. The cells without roman indices are used to better illustrate the allocation rules of the initial pilot group in the adjacent sub-direction. For example, the starting sectors in sub-direction 2 and sub-direction 3 are sector 2 of cell IX and cell XV, respectively, and as shown in fig. 2, pilot groups a and B are allocated to the starting sectors in adjacent sub-directions on Dir 1, respectively.
As shown in fig. 2, by using the smart antenna technology, the base station only receives signals from users in the shadow coverage area in each direction, each pilot group is orthogonal to each other, and for the target direction of the interested user, each pilot group in the other direction is invoked twice in the shaded coverage area, considering sector 5 of cell I, we can see in figure 2 that pilot set D-E-F on Dir 2 and pilot set G-H-J on Dir 3 are both called twice in the shaded coverage area, in the phase of transmitting pilot frequency to the base station by each user, the user in sector 5 of cell I is only interfered by the user in sector 2 of cell xviiii, compared with the traditional CSP scheme, the most troublesome interference source (user of cell VI) disappears, and the number of interference sources of the proposed scheme is reduced to 1, therefore, the proposed pilot allocation strategy based on cell sectorization can well suppress pilot pollution.
Meanwhile, the number of pilots in each coverage area is determined by the following method:
for each coverage area, N pilot frequencies are randomly taken out from 3N/2 mutually orthogonal pilot frequencies and are arranged in 2(L-1)/3 sectors in the coverage area, wherein the probability of arranging the pilot frequencies in each sector in the coverage area is 2(L-1)/3N after the arrangement is finished, then the rest N/2 pilot frequencies are distributed to the rest (L-1)/3 sectors, and the pilot frequency distribution based on cell sectorization in a Massive MIMO system is finished.
For example: when the number of cells is 19, each cell is divided into 6 sectors, 9 pilots exist, the 6 pilots are firstly filled in the 12 sectors, each pilot appears 12/N times, and then the remaining 3 pilots are allocated to the remaining 7 grids.
Thus, the conventional CS-PA scheme can better suppress pilot pollution as the cell is divided into more sectors.
It should be noted that L is 19, pilot setting power is 13db, transmit power at the base station end is 20db, radius of each cell is 600m, in the process of signal transmission, coherence time includes two time slots, each time slot is 0.5ms, and each cell is equally divided into N sectors according to the smart antenna technology.
As shown in fig. 3, in order to solve the problem of pilot pollution, in the conventional TSP algorithm, users in different cells send pilots in non-overlapping time slots, and such mutually exclusive pilot transmission in time domain prevents mutual pollution of non-orthogonal pilots in adjacent cells. Although the conventional TSP algorithm suppresses pilot pollution, reduces pilot overhead, and increases system capacity, the conventional TSP algorithm has two limiting factors:
(1) as shown in fig. 3, the number of service users in a single carrier scenario is only 1/3 of the coherence time length, which is less than the optimal number of service users in the traditional CSP scheme, which is 1/2 of the coherence time length;
(2) the uplink transmission pilot frequency and the downlink transmission data of different cells are overlapped on a time slot and interfere with each other, and compared with pilot frequency pollution, the pilot frequency interference is replaced by data interference with larger power. In addition, under a system model including more cells, the conventional TSP scheme is inevitably limited to more serious interference between the uplink pilot and the downlink data.
The present invention integrates the time-shifted pilot structure with the conventional CS-PA scheme, and for simplicity, if not specifically described below, the present invention assumes that the system parameters are set by default to the number of sectors N-6 and 3N/2 orthogonal pilots. Comparing fig. 3 and fig. 4, it is found that the present invention transmits training sequences over non-overlapping time slots for users in different directions, rather than for users in different cells.
In order not to increase the redundancy of letters, the serial numbers of the orthogonal pilot frequency groups in the invention are still represented by capital English letters A-J. In this way, the users on Dir 1 transmit orthogonal pilot groups a, B, C; transmitting orthogonal pilot frequency groups D, E and F by users on the Dir 2; users on Dir 3 transmit orthogonal sets of pilots G, H, J. Assuming that one user is in each sector, considering Dir 1 as the interested user, the uplink interference analysis and the downlink interference analysis will be performed below.
And (3) uplink interference analysis: in Slot Period 1, users on Dir 1 transmit uplink pilot frequency, and users of Dir 2 and Dir 3 receive downlink data. For the users in sector 5 of Cell I, the pilot interference only originates from sector 2 of Cell XVIII; and data interference originates from sector 1 of Cell XI and sector 3 of Cell XII. It follows that the number of interferers is a compromise compared to the conventional CS-PA scheme and TSP scheme. Considering the jth cell base station on Dir 1, its receive vector is expressed as:
wherein, BijAndrespectively representing a small-scale fading matrix and a large-scale fading coefficient between the ith antenna and the jth antenna; [ S ]i]mk＝simkAnd indicating the precoded symbols transmitted by the mth antenna of the ith base station to the kth user of the cell. Therefore, the pilot interference of the part received by the base station of the jth cell is replaced by the data interference on Dir 2 and Dir 3.
And (3) downlink interference analysis: in Slot Period 2, users on Dir 1 and Dir 3 receive downlink data, users on Dir 2 transmit uplink pilot frequency, and for users in sector 5 of Cell I, pilot frequency interference traverses all cells; and data interference originates from sector 1 of Cell XI, Cell V, and Cell XVII and sector 4 of Cell XIII, Cell II, and Cell XIV. Without loss of generality, consider the 1 st cell base station on Dir 1, whose received vector is represented as:
wherein,representing the precoding moment of the jth base station in the previous coherence timeArraying; u shapeijAnd αijRepresents the small-scale and large-scale fading matrixes between the users of the 1 st cell and the jth cell, so that part of the data interference received by the base station of the 1 st cell is replaced by the pilot interference on the Dir 2.
The performance of the present invention is compared to conventional CSP and TSP schemes to demonstrate the effects achievable by the present invention, as shown.
As can be seen from fig. 5, the MTSP is the scheme of the present invention, which has significant performance advantages compared to the conventional CS-PA scheme and TSP scheme, because the cell sectorization and time shift pilot structure, the scheme of the present invention achieves twice the system capacity of the TSP scheme and reduces the pilot overhead compared to the conventional CS-PA scheme, and fig. 5 also shows that when the number of antennas is small, the conventional TSP scheme has some performance advantages compared to the conventional CS-PA scheme, but the conventional CS-PA scheme is superior as the number of antennas increases. This is because when the number of base station antennas is small, the system performance is limited by the degree of freedom per user, while the degree of freedom of users in the conventional CS-PA scheme is low; conversely, when the number of base station antennas is large, the system performance is limited to the total number of users served by the scheme, while the TSP scheme is limited to users served by its own pilot structure.
For comparison, in fig. 6, in the case of serving the same number of users, the system capacity simulation of the present invention in which the cell is divided into different sectors N is compared, and each sector contains 12/N users, the pilot overhead increases as the number of users per sector increases. As can be seen in fig. 6, when the cell is divided into more sectors, the system as a whole can achieve greater capacity due to better pilot pollution suppression and less pilot overhead. As can also be seen in fig. 6, when the number of base station antennas is small, the higher degree of freedom of a single user makes the performance of the small number of sectors better; conversely, a higher number of sectors makes the scheme converge more slowly because of the lower degrees of freedom.
Fig. 7 compares the capacity of the present invention versus the prior art scheme as a function of pilot transmit power, where MTSP is the scheme of the present invention, where it can be seen that the curves of the present invention versus the prior art TSP scheme are convex because both uplink and downlink transmit data, both too large and too small pilot transmit power, reduce the system capacity. It can also be seen that the present invention and the existing CSP schemes converge slowly without being affected by the above-mentioned interference. The fixed data transmission power is unchanged, and the invention can maximize the system performance through the optimal pilot frequency transmission power. Simulation results show that the optimal pilot frequency transmitting power of the invention is lower than that of the existing TSP scheme, but larger system capacity can be realized.
In conclusion, compared with the existing CSP scheme, the pilot frequency pollution problem can be better inhibited; the present invention serves more users than existing TSP schemes without increasing pilot overhead.
Claims (5)
1. A pilot frequency distribution method based on cell sectorization in Massive MIMO system is characterized by comprising the following steps:
1) setting a base station end in a Massive MIMO system to be configured with M antennas, simultaneously setting K UEs and L surrounding cells in the Massive MIMO system, wherein each user corresponds to one antenna, dividing each cell into N sectors, and sequentially numbering the sectors in each cell in an anticlockwise direction, wherein the position of a first sector in each cell is the same, the number of mutually orthogonal pilot frequencies is 3N/2, and each sector is set to correspond to one user;
2) obtaining a cell model according to a sector uniform division method, then dividing all sectors in the cell model into N/2 types of directions, wherein the ith type of direction is the direction from the ith sector to (N +2i)/2 sectors, wherein i is more than or equal to 1 and less than or equal to N/2, then averagely dividing the L surrounding cells into N coverage areas by taking each sector in a middle cell as a vertex, then the total number of the sectors in each coverage area is L, then dividing the sectors in the coverage areas according to the N/2 types of directions, then averagely dividing all pilots into N/2 pilot groups, then the number of the pilots in each pilot group is 3, then sequentially distributing the pilot groups to the various directions, then circularly distributing the pilots in the pilot groups to the sectors in the corresponding type of directions, and enabling each cell to have the pilot groups at the same time, and the pilot frequencies corresponding to the adjacent sectors are different, wherein the result of N/2 is a positive integer, and the result of (L-1)/3 is a positive integer;
meanwhile, the number of pilots in each coverage area is determined by the following method:
for each coverage area, N pilot frequencies are randomly taken out from 3N/2 mutually orthogonal pilot frequencies and are arranged in 2(L-1)/3 sectors in the coverage area, wherein the probability of arranging the pilot frequencies in each sector in the coverage area is 2(L-1)/3N after the arrangement is finished, then the rest N/2 pilot frequencies are distributed to the rest (L-1)/3 sectors, and the pilot frequency distribution based on cell sectorization in a Massive MIMO system is finished.
2. The method of claim 1, wherein N is 2, 4, 6 or 12.
3. The method of claim 1, wherein L is 19, pilot setup power is 13db, and transmit power at the base station is 20 db.
4. The pilot frequency allocation method based on cell sectorization in Massive MIMO system according to claim 1, wherein the radius of each cell is 600m, the coherence time comprises two time slots in the process of signal transmission, and each time slot is 0.5 ms.
5. The pilot allocation method based on cell sectorization in Massive MIMO system according to claim 1, wherein each cell is equally divided into N sectors according to smart antenna technology.
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| US10063396B2 (en) | 2016-02-05 | 2018-08-28 | Hong Kong Applied Science and Technology Research Institute Company Limited | Method and apparatus of topological pilot decontamination for massive MIMO systems |
| WO2017132984A1 (en) * | 2016-02-05 | 2017-08-10 | Hong Kong Applied Science and Technology Research Institute Company Limited | Method and apparatus of topological pilot decontamination for massive mimo systems |
| CN106850173B (en) * | 2017-01-19 | 2020-05-05 | 南京邮电大学 | Multi-cell pilot frequency distribution method based on large-scale MIMO |
| CN108462565B (en) * | 2018-02-08 | 2021-08-10 | 北京交通大学 | Optimal pilot frequency distribution system and method for 5G high-frequency-band wireless backhaul |
| CN109474548B (en) * | 2018-11-16 | 2022-03-18 | 郑州云海信息技术有限公司 | Pilot pollution elimination method based on deep learning regulation and control sector |
| CN110086591B (en) * | 2019-05-14 | 2021-10-22 | 鹰潭泰尔物联网研究中心 | Pilot pollution suppression method in large-scale antenna system |
| CN110545166B (en) * | 2019-08-08 | 2021-12-28 | 南瑞集团有限公司 | Pilot frequency multiplexing method based on continuous pilot frequency multiplexing factor |
| CN110505702B (en) * | 2019-09-29 | 2023-07-25 | 重庆大学 | Pilot frequency distribution method based on user signal arrival angle |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1194554A (en) * | 1997-02-19 | 1998-09-30 | 朗迅科技公司 | Multistage sectorial CDMA communication |
| CN101341786A (en) * | 2005-10-27 | 2009-01-07 | 高通股份有限公司 | Pilot symbol transmission in wireless communication systems |
| CN103281169A (en) * | 2006-03-20 | 2013-09-04 | 富士通株式会社 | Communication method, base station, mobile station and wireless communication system |
| CN103634816A (en) * | 2013-11-01 | 2014-03-12 | 南京邮电大学 | Method for eliminating pilot pollution-based interference in multi-cell massive MIMO (Multiple Input Multiple Output) |
-
2014
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1194554A (en) * | 1997-02-19 | 1998-09-30 | 朗迅科技公司 | Multistage sectorial CDMA communication |
| CN101341786A (en) * | 2005-10-27 | 2009-01-07 | 高通股份有限公司 | Pilot symbol transmission in wireless communication systems |
| CN103281169A (en) * | 2006-03-20 | 2013-09-04 | 富士通株式会社 | Communication method, base station, mobile station and wireless communication system |
| CN103634816A (en) * | 2013-11-01 | 2014-03-12 | 南京邮电大学 | Method for eliminating pilot pollution-based interference in multi-cell massive MIMO (Multiple Input Multiple Output) |
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